Recently, interest in the millimeter-wave spectrum at 10 GHz to 300 GHz has drastically increased. The emergence of low cost high performance CMOS technology has opened a new perspective for system designers and service providers because it enables the development of millimeter-wave radios at the same cost structure of radios operating in the gigahertz range or less. In combination with available ultra-wide bandwidths, this makes the millimeter-wave spectrum more attractive than ever before for supporting a new class of systems and applications ranging from ultra-high speed data transmission, video distribution, portable radar, sensing, detection and imaging of all kinds. However, taking advantage of this spectrum requires the ability to design and manufacture reliable, low cost, efficient antennas operating with millimeter-wave semiconductor devices.
In millimeter wave systems, such as, e.g., radars for automotive safety and comfort, antenna structures are placed on high frequency substrates or high frequency printed circuit boards (HF PCBs). Antennas such as microstrip antennas (e.g., patch antennas) are often built on these special high frequency substrates. HF PCBs are often constructively based on Rogers, Taconic or other PTFE materials. However, such construction increases the overall cost due to the extra high expense of such high frequency substrates and their assembly.
Millimeter wave output power can be generated on a semiconductor monolithic microwave integrated circuit (MMIC), which may be located also on the HF PCB. The inputs and outputs on MMIC devices frequently match to a characteristic impedance (e.g. 50 ohms) and interconnect to an antenna. These interconnections between MMIC devices and antenna generally involve a lossy chip/board interface (e.g., bond wires).
Therefore, there is a demand for efficient, less expensive, and cost-effective antenna packages for millimeter wave applications.